Modulation of Gamma Ray–Induced Genotoxic Effect by Thymol, a Monoterpene Phenol Derivative of Cymene

Abstract

The radioprotective effect of thymol (TOH), a monoterpene phenol, on radiation-induced DNA damage was analyzed in vitro. Chinese hamster lung fibroblast cells (V79) were treated with different concentrations of TOH (0-100 µg/mL) for 1 hour before exposure to 3 Gy gamma irradiation, and then cytokinesis-blocked micronucleus and single-cell gel electrophoresis (comet assay) assays were used to evaluate the radiation-induced cytogenetic damage and genotoxic effects. Furthermore, the modulating effect of TOH on radiation-induced cell death was assessed by apoptotic and necrotic cell detection by staining with ethidium bromide/acridine orange using fluorescence microscopy. To understand the mechanism of TOH-imparted cytoprotection, mitochondrial membrane potential (MMP) was detected by flow cytometry after staining the cells with Rhodamine 123. Pretreatment of V79 cells with various concentrations of TOH (0-100 µg/mL) for 1 hour reduced the radiation-induced micronuclei as well as percent tail DNA and mean Olive tail moment with a maximum protective effect observed at TOH (25 µg/mL). Apoptosis by microscopic, MMP measurements indicated that the V79 cells exposed to gamma radiation alone showed a maximal increase in the number of early and late apoptotic and necrotic cell death associated with a significant loss of the MMP. Pretreatment with TOH (25 µg/mL) showed a significant (P < .01) decrease in the level of apoptotic fraction as well as necrotic cells and suppressed the radiation-induced collapse of MMP when compared with the radiation alone group. These results suggest that TOH suppresses radiation-induced genotoxicity, apoptosis, and necrosis primarily by the free radical scavenging and modulation of oxidative stress.

Effect of free thymol on differential gene expression in gastric mucosa of the young pig

“…First, we provide strong evidence that thymol activates genes involved in mitosis and mitosis regulation. Although no previous study has reported direct evidence regarding the effect of thymol on mitosis, thymol has been shown to reduce gamma radiationinduced apoptosis in V79 cells (Archana et al, 2011), primarily by the modulation of intracellular antioxidant levels and free radical scavenging. It is also likely that carvacrol, another monoterpenic phenol structurally similar to thymol, stimulates mitosis and liver tissue regeneration after partial hepatectomy (Uyanoglu et al, 2008).…”

Pharmacological Properties and Molecular Mechanisms of Thymol: Prospects for Its Therapeutic Potential and Pharmaceutical Development

“…It has also shown moderate antioxidant activity in V79 Chinese hamster lung fibroblast cells (Undeger et al, 2009). Thymol (25 μg/ml) showed potent antioxidant activity by modulating the activities of enzymatic antioxidants and decreased lipid peroxidation in gamma ray induced V79 Chinese hamster cells (Archana et al, 2011b). Thymol (0.02–0.20%) showed better antioxidant capacity than its isomer carvacrol in lipid systems due to its greater steric hindrance and it was shown that at room temperature it inhibited the autoxidation of two lipid systems namely triacylglycerols of lard (TGL) and triacylglycerols of sunflower oil (TGSO).…”

“…Owing to its potent antioxidant potential, thymol showed radioprotective and anticlastogenic potential in gamma radiation induced Swiss albino mice (Archana et al, 2011b). Thymol supplementation increased the antioxidant status and decreased malondialdehyde (MDA) levels in broiler chickens (Zidan et al, 2016).…”

Use of natural substances for boar semen decontamination

“…It is highly soluble in ethanol, dilute hydroxide solutions, ether, paraffin oil and glycerol. At higher concentrations, thymol may evoke skin and mucosal irritation (Elissondo et al 2008;Lee et al 2008;Bassole et al 2010;Archana et al 2011). Besides damaging the bacterial cytoplasmic membrane with the subsequent death of bacteria, damage to the bacterial cell wall and the inhibition of some bacterial enzymes has also been reported (Farag et al 1989).…”